1. Field of the Invention
The present invention relates to an outsole for a sports shoe and to a sports shoe including such an outsole, in particular a soccer shoe.
2. Background
In many sports, acceleration influences the performance of an athlete. For example, in the case of a sprinter, it is not only the ultimate achievable speed that influences victory or defeat, but also how quickly this speed is reached. Acceleration is even more important in sports in which frequent changes of direction are common. In particular for soccer, but also for other field sports, athletes frequently accelerate when, for example, they change direction while running or jump suddenly.
According to the laws of physics, acceleration directly depends on the mass to be moved. It is therefore an important objective in the design of sport shoes, in particular soccer shoes, to reduce the overall weight as much as possible in order to increase the acceleration at a given force. Presently, the lightest available soccer shoes have a weight of greater than 165 grams. Even such a weight, which might seem minor, may impair a player's agility, e.g., during fast dribbling with a soccer ball. Furthermore, the inertial mass of the soccer shoe may reduce the velocity of the player's leg when kicking the ball and thus reduce the speed of the kicked ball. Also, the inertial mass of the soccer shoe at the player's legs may affect the fatigue of the player. The larger the mass that exerts leverage forces and torques on the body due to its positioning at the lower extremities, the faster the player may fatigue during the 90 minutes (or more) of a soccer match.
A number of conventional approaches attempt to reduce the weight of a shoe. US Patent Application Publication No. 2009/0071036, published Mar. 19, 2009, for example, discloses the use of carbon fibers in the upper part of a shoe. US Patent Application Publication No. 2007/0271823, published Nov. 29, 2007, for example, discloses an upper wherein a thin material layer is reinforced by a plurality of threads arranged on its outside. U.S. Pat. No. 4,813,158, issued Mar. 21, 1989, for example, discloses a lightweight sports shoe having reinforcement in the transition area between midfoot and forefoot so that the shoe is capable of withstanding loads in spite of the thin and lightweight materials of the upper. U.S. Pat. No. 7,540,097 B2, issued Jun. 2, 2009, for example, discloses a shoe construction wherein the upper comprises a dense matrix structure of repeatedly intersecting segments. The upper itself may be arranged within the matrix structure so that the segments are arranged on the outside of the upper.
Apart from addressing the upper of the shoe, some conventional approaches also modify the sole structure, since the sole of the shoe has an influence on the overall weight of the shoe. The US Patent Application Publication No. 2009/0064535, published Mar. 12, 2009, for example, discloses a sole assembly wherein a plate made from a composite material is glued to a cut-out of a sole.
None of the above-described approaches, however, substantially reduce the weight of a sports shoe without deteriorating its functional properties (e.g., traction on the ground, support for the foot, and wearing comfort) or without substantially increasing manufacturing complexity and/or cost.
The present invention at least partly overcomes the disadvantages of known shoe constructions by providing an outsole and a sports shoe that may have substantially reduced weight compared to conventional outsoles and sports shoes but that may maintain stability, wearing comfort, and/or traction, and/or that can be affordably manufactured.